Supercoated transfer elements



March 12, 1963 D. A. NEWMAN ETAL 3,080,954

SUPERCOATED TRANSFER ELEMENTS Filed May 20, 1960 vpmm/ il .fo

United States Patent() 3,080,954 SUPERCOATED TRANSFER ELEMENTS Douglas A. Newman, Glen Cov'e, and Allan T. Schlotzbauer, Locust Valley, N.Y., assignors to Columbia Ribbon and Carbon Manufacturing Co. Inc., Glen Cove, N.Y., a corporation of New York Filed May 20, 1960, Ser. No. 30,621 Claims. (Cl. 197-172) The present invention is concerned with novel, clean, long-life transfer ribbons and the method of their produc` tion.

Typewriter ribbons are the most commonly employed transfer media in use t-oday. However, conventional ribbons are recognized to have numerous disadvantages and it is an object of the present invention to overcome many of these disadvantages.

Conventional typewriter ribbons are very dirty to the touch. Thus, in removing a used ribbon from a typewriter and installing a new one, the hands of the typi-st become greatly soiled due to exposed ink on the ribbon. This soil in turn is unintentionally transferred to the typewriter keys and to the work being done, etc.

Another disadvantage is encountered in attempting toproduce ribbons which have a relatively long life. The ribbon must contain an excess of ink. However, when a large amount o-f ink is used it gives 4rise to many prob-- lems. The ribbon produces excessively-inked images which tend to smudge and spread on the sheet. Also,

excess ink on the ribbon tends to accumulate on the rib-L bon guides of the typewriter due lto abrasion and fall onto the work or the roller, etc.

Still another disadvantage encountered in the producf tion of fab-ric textile typewriter ribbons larises from the fact that they are generally produced as wide webs which are thereafter cut into strips. the ribbon edges are heat sealed or otherwise treated to insure uniform thickness across the ribbon and to prevent uneven edges.

It is an object of the present invention to produc transfer ribbons which are exceedingly clean to the touch but which nevertheless have a very long life and write uniformly and sharply.

It is a fur-ther objectof the preferred form of the present invention to prepare ribbons of fabric textile which do not require the extra step of sealing their edges.

Other important advantages of this invention will be clear to those skilled in the art, as will the particular nature of the present invention, upon consideration of the detailed description set forth herein.

In the drawing:

FIGURES l through 3 are fragmentary perspective views of different forms of typewriter ribbons prepared according -to the present invention.

The objects of the present invention are accomplished by overcoating an inked ribbon of the textile fabric type on at least one surface with a porous, spongy, honey,- comb layer comprising a synthetic resin, non-volatie, nonsolvent material, and, if desired, an amount of coloring matter. It has been found that this supercoating, even where pigmented itself, is very clean to the touch since it is porous and, apparently due to capillary action, holds the inkl and non-volatile, non-solvent material within its pores to provide a substantially ink-free surface. Secondly, although the supercoating acts as a protective coating, it transmits ink from the inner textile fabric ribbon to a copy sheet under the pressure of a type bar, provided that the ink composition of the textile ribbon andthe composition of the superooating are formulated according to the description set forth hereinbelow.

Referring to the drawing, FIG. 1 depicits an inked textile fabric ribbon 20 having the porous, protective ink- Care must be taken that textile fabric ribbon 20 is supere-cated on one surface with a porous, protective, ink-'transmitting coating 10. As above, this coating comprises a honeycomb or foundation of synthetic resin material having pores 11 therein containing a nonvo1atile material, such as mineral oil, which is a non-solvent for the synthetic resin material employed,

type bars.

FIG. 3 shows a typewriter ribbon 40 prepared by inking a textile fabric ribbon with a pore-forming resinous ink composition which results in the body of the ribbon being impregnated therewith and containing microp-ores 41 which carry non-volatile, non-solvent material and pigment or dye. The thus inked ribbon is then supercoated on both `sides with pore-forming resinous composition, preferably devoid of pigment or dye, to form an exceptionally clean and long life ribbon having a supercoa-ting 10 carrying micropores 11 having therein nonvolatile, nonsolvent material which is the same as, or at least compatible with, the non-volatile, non-solvent material in pores 41 of the ribbon.

The present invention is applicable to all types of textile fabric ribbons whether they are of the woven or matted type. Conventional ribbons formed from cotton, silk, nylon, felt or any of the other textile fabrics which act as reservoirs for ink compositions may be treated according to the method set forth hereinbelow. However, the ink composition with which the body of the textile fabric ribbon is impregnated, prior to application of the supercoating, must be carefully controlled. It is essential that the non-volatile vehicle of this ink composition contain no material which is a solvent for the synthetic resin material of the supercoating. The use of such solvent materials as dibutyl phthalate or tricresyl phosphate as vehicles, softeners or carriers in the ink composition tends to destroy the porous character of the supercoating, sealing it and rendering it ink non-transmitting- It must be understood, however, that the ink composition of the textile fabric ribbon will vary depending upon the nature of the synthetic resin material used in the supercoating, variations being well within the skill of the artisan. It has also been found to be important that the carrier or softener of the ink composition in lthe body of the fabric ribbon be compatible and miscible with the non-volatile material carried within the pores of the supercoating. For instance, excellent results are obtained where the ink carrier of the fabric ribbon and the non-volatile ingredient of the supercoating are both oils, and preferably the same oil such as mineral or vegetable oil. The ink composition with which the ribbon is initially treated may comprise any of the conventional ribbon inking compositions presently in use, with the solubility and compatibility limitation discussed above, or else the ribbon inking composition may comprise the same composition employed as the porous supercoating. For instance, the ribbon may be inked with a composition as set forth in our U.S. Patent No. 2,820,717 and passed through rollers prior to evaporation of the solvents. This causes uniform impregnation of the ribbon and results in the ribbon 40 impregnated with a porous honeycomb ink layer having ink-containing pores 41 as shown by FIG. 3 of the drawing. ln this embodiment, preferably the supercoating layer contains no coloring matter within its pores 11.

It should be understood, however, that Where it is desired to impregnato the ribbon with the pore-forming ink composition, such composition may be selected from any of the pigmented supercoating compositions named and var'ed greatly as may the supercoating composition.

Broadly speaking, the supercoating composition compirses a resinous pore-forming material together with a non-volatile component which is a non-solvent for the resin and, if desired, pigment or dye, whereas if the ribbon is impregnated with pore-forming ink composition, rather than a conventional ink composition, this com position always contains pigment or dye.

As the resin of the pore-forming compositions which set to a porous, spongy layer, unsaturated polymers such as polyvinyl chloride, polyvinyl fluoride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers of the Vinylite series such as Vinylite VYHH, polyvinyl butyral, polyacrylic acid, polystyrene, polyvinylidene chloride (Saran), others; hydrocarbon polymers such as polyethylene and polypropylene; polyurethanes obtained by reacting an isocyanate such as toluene di-isocyanate with a hydroxylcontaining compound such as an alkyd resin or a glycol; polyamides such as alcohol-soluble nylon, as well as many others, may be used.

No particular criticality exists in the selection of the pore-forming material but soft vinyl chloride-vinyl acetate copolymers such as Vinylite VYHH are particularly well suited because of their softness, flex strength and adherence for the underlying tex-tile fabric ribbon.

The pore-forming layer may be applied to the preinked ribbon in any desired manner.

in the preferred embodiment, the resinous porc-forming material together with the non-volatile, non-solvent component and pigment or dye are dissolved in a suitable solvent such as a 3 :l mixture of ethyl acetate and toluol and the mixture ground to a suitable coating viscosity. The mixture is then spread evenly over one or both surfaces of the pre-inked textile fabric ribbon by suitable coating apparatus or by immersing the ribbon in a vat containing the mixture, and allowed to cool and harden by evaporation of the volatile ingredients to form a smooth, pressuretransferable ink-releasing ribbon of the type disclosed. lt has been found advantageous to heat the final ribbon for a short time to a temperature of 160 C. or above to fuse the supercoating to the fabric ribbon.

In the selection of a material suitable as the non.

volatile component, two critical requirements must be observed. Such material must be a non-solvent for the resinous pore-forming material and also be compatible with the ink carrier or vehicle of the fabric ribbon. in general, non-volatile mineral, vegetable and animal oils are found most satisfactory, such as naphthenic mineral oil, treats-foot oil, rapeseed oil, cottonseed oil, peanut oil, castor oil, olive oil, sperm oil, etc. Materials such as butyl stearate, lanolin, petrolatum and hydrogenated vegetable oil have been used successfully, particularly in admixture with the above-named oils. Fatty acids and esters may also be used, such as oleic acid, isopropyl palmitate, diglycol lsurate and diglycol oleate.

ln another embodiment of the present invention, the resinous pore-forming material may be compounded and applied using little or no volatile components. For instance, the resinous material such as Vinylite VYI H or VYNC may be suspended as a finely divided dispersion in either an organic liquid vehicle containing minor amounts of a volatile dispersing liquid, in which case the dispersion is called an organosolj or in a completely non-volatile dispersing liquid in which case the dispersion is called a plastisch Such dispersions may be compounded in any conventional manner and are described by Schildknecht in Vinyl and Related Polymers (1%2) at page L34 and followin". Such dispersions contain a plasticizer such as di-(Z-ethylhexyl) phthalate, dioctyl sebacatc and dibutoxyethyl phthalate which act as dispersing agents at room temperatures and keep the resin at a eoatable consistency and which act as solvents at elevated temperatures over about C. to provide a homogeneous hlm upon fusion at this temperature.

It has been found that when any of the non-volatile, non-solvent components referred to above, such as the mineral, vegetable and animal oils, are incorporated into such organosols or plastisols, together with. coloring matter if desired, and applied to one or more surfaces of the pre-inked textile fabric ribbon and fused at elevated ternperatures, there results, on cooling, the formation of a porous, spongy, inloreleasing element of the same type prepared using volatile solvents. This is important in cases where it is desired to avoid the hazards of using such volatile solvents.

The ribbons prepared in this manner have an exceptionally long life due in part lto the fact that the supercoating serves to meter or regulate the quantity of ink solution which is transferred to an underlying sheet under the impact of the type bar. This prevents the transfer of too much ink and provides for uniform ink transfer and thus uniformly toned copies.

Where it is desired to produce a type writer ribbon having only its imaging surface supercoated as shown by FIG. 1, this is accomplished preferably by applying a coating of the resinous pore-forming composition to a wide web of the inked textile fabric, allo-Wing the composition to set, and then cutting the coated web into a plurality of strips or ribbons in known manner.

Where it is desired to produce a ribbon in accordance with FIG. 2 of the drawing, this is accomplished preferably in the same manner as above, except that prior to cutting the web into individual ribbons, the supercoated web is coated on its opposite side with an ink-impervious, continuous layer of plastic film or resin composition. This is done, for instance, by applying a thin lilm of synthetic resin comprising any of the synthetic resin materials employed in the porous protective layer, dissolved in a volatile solvent therefor, to the unprotected side of the fabric ribbon and allowing the solvent to evaporate. No non-volatile material is used in this coating and so the resin composition sets to a continuous, ink-impervious layer 39. If desired, layer 30 may be applied prior to layer l0, or both layers may be applied simultaneously. Another method of applying layer 30 is to use a selfsustaining lrn of material such as Mylar, Saran or the Vinylites such as VYHH and adhere it to the fabric ribbon through the use of adhesives.

When it is desired to prepare a ribbon which is supercoated on both sides as shown by Flf. 3 of the drawing, the wide web of textile fabric is coated, preferably simultaneously, on both sides with the resinous pore-forming composition. In this manner it has been found that the ribbon does not require the extra step of sealing the loose edges since the supercoating accomplishes this result by adhering to any loose threads or filaments and binding them to the ribbon body.

lt should be understood that many variations may be made within the scope of the present invention. For instance, the ribbons shown by FIGS. l and 2 of the drawing may be inked vwith resinous pore-forming ink composition rather than conventional ribbon ink. Likewise, in any of the supercoatings ti, the pores il may or may not be supplied with pigment or dye depending upon Whether a ribbon of exceptionally long life or a ribbon of exceptional cleanliness is desired. Also the ribbon shown by FIG. 3, for instance, may carry pigment in the supercoating on the imaging surface of the ribbon and no pigment in the, supercoating facing the type bars.

Variations and modifications may be made within the scope4 of the claims and portions of the improvements may be usedwithout others.

We claim:

1. A pressure-sensitive transfer element comprising a flexible foundation bearing an inkre1easing composition containing imaging material and a non-volatile vehicle, and having on the surface of said composition a porous, spongy, ink-transmitting supercoating comprising a vinyl resin and a non-volatile oily material which is a non-solvent for said resin, said non-vo1atile vehicle being miscible ywith said oily material and also ybeing a non-solvent for said resin.

2. A typewriter ribbon according to claim 1 in which the flexible foundation comprises a fabric and the inktransmitting supercoating is present on the front surface of the fabric and the back surface has attached thereto a continuous, ink-impervious -resinous coating.

3. A typewriter ribbon according to claim 1 in which the supercoating also contains imaging material.

4. A typewriter ribbon according to claim 1 in which the vehicle of the ink-releasing composition and the oily material of the supercoating each comprises mineral oil.

5. A pressure-sensitive transfer element according to claim 1 in which the ink-releasing composition comprises a porous, spongy, resinous composition comprising a vinyl resin, a non-volatile oily vehicle which is a nonsolvent for said vinyl resin and a quantity of imaging material.

6. The process of producing pressure-sensitive transfer elements which are clean to the touch and which have a relatively long life which comprises coating a exible foundation with an ink-releasing composition containing imaging material and a non-volatile vehicle, and applying to the surface of said coating an ink-transmitting supercoating of resinous composition comprising a vinyl resin and a non-volatile oily material which is -a non-solvent for said resin, said non-volatile vehicle of the ink composition being miscible with the non-volatile oil material of the supercoating and also being a non-solvent for said resin, and allowing said supercoating to set whereby is formed as the continuous phase a porous, substantially non-pressuretransferable layer of said resin containing as the discontinuous phase said non-volatile oily material.

7. The process of clairn 6 in which the vehicle of the ink composition and the oily material of the supercoating each comprises mineral oil.

S. The process of claim 6 in which the ink-releasing composition comprises a Vinyl resin, a non-volatile oily vehicle which is a non-solvent for said vinyl resin and a quantity of imaging material.

9. The process of claim 6 in which the ilexible foundation comprises a fabric and the supercoating is applied to the front surface of the fabric and the back surface of the fabric has attached thereto a protective, continuous, ink non-transmitting layer.

10. The process of claim 6 in which the supercoating also contains imaging material.

References Cited in the tile of this patent UNITED STATES PATENTS Newman et al. Jan. 21, 1958 

1. A PRESSURE-SENSITIVE TRANSFER ELEMENT COMPRISING A FLEXIBLE FOUNDATION BEARING AN INK-RELEASING COMPOSITION CONTAINING IMAGING MATERIAL AND A NON-VOLATILE VEHICLE AND HAVING ON THE SURFACE OF SAID COMPOSITION A POROUS SPONGY, INK-TRANSMITTING SUPERCOATING COMPRISING A VINYL RESIN AND A NON-VOLATILE ONLY MATERIAL WHICH IS A NON-SOLVENT FOR RESIN, SAID NON-VOLATILE VEHICLE BEING MISCIBLE 